Abstract: A mixer facilitates dissolving a lower density material into a higher density material using a rotating paddle to create a highly turbulent mixing zone in a mixing chamber adjacent to the flow of the higher density material. In an illustrated example, the mixer includes a motor that drives a mixing paddle to create a highly turbulent mixing of a liquid and a gas in the mixing chamber. The mixing paddle resides in a paddle chamber connected to the liquid transfer pipe by the mixing chamber. The mixing paddle is preferably just outside the opening from the paddle chamber to the mixing chamber for increased turbulence in the mixing chamber. A portion of the liquid flowing in the transfer pipe enters into the mixing chamber, mixes with the gas, and the mixture flows back into the transfer pipe.